It is disturbing how many in our churches are unwilling even to
consider the possibility of false teachers being among us. It
ought to be painfully evident from history that such have been
a regular feature of the life of the church. Sadly, in our day
most would rather not consider it a possibility and therefore
keep their minds firmly shut and change the subject when it is
mentioned. Yet the Apostle Paul clearly knew that false teachers
would arise. When he spoke to the Ephesian elders before his final
trip to Jerusalem he warned them that after his departure savage
wolves would enter the flock from outside (Acts 20.29). Even more
disturbingly he warned them that even from among themselves men
would rise up speaking perverse things, to draw away the disciples
after themselves (v30).

False teaching is inevitable. It is part of the work of Satan
in trying to hinder the work of the Church. Yet, the division
which it creates is not necessarily bad or wrong. Indeed there
must also be factions among you, in order that those who are approved
may be recognised among you (1 Cor 11.19).